Immunological and angiogenic markers during metronomic temozolomide and cyclophosphamide in canine cancer patients.

Metronomic chemotherapy stimulates the immune response via depletion of regulatory T cells (Tregs) and suppresses angiogenesis by modulating the secretion of thrombospondin-1 (TSP-1) and vascular endothelial growth factor (VEGF). In this study, blood was collected from 10 healthy dogs and from 30 canine cancer patients before and 2 and 4 weeks after treatment with metronomic temozolomide (6.6 mg m-2 ), cyclophosphamide (12.5 mg m-2 ) or cyclophosphamide and temozolomide. The percentage of circulating CD25+ Foxp3+ CD4+ Tregs and the plasma levels of TSP-1 and VEGF were measured. There was a significant difference in the percentage of Tregs between cancer patients and healthy dogs. A significant decrease in Tregs was noted in patients treated with metronomic cyclophosphamide and the combination. Treatment with temozolomide had no effect on the percentage of Tregs. TSP-1 and VEGF levels were, respectively, significantly lower and higher in cancer patients than in healthy dogs, but they were not influenced by any of the studied metronomic treatment regimens.

Prepubertal gonadectomy in cats: different surgical techniques and comparison with gonadectomy at traditional age.

Feasibility, surgical time and complications of different surgical techniques for prepubertal gonadectomy (PPG; 8-12 weeks of age) in cats were studied and compared to gonadectomy at traditional age (TAG; 6-8 months of age). Kittens were randomly assigned to PPG or TAG. Ovarian pedicle haemostasis for PPG was achieved by ligatures (n=47), vascular clips (n=50), bipolar electrocoagulation (n=50), or pedicle tie (n=50); for TAG (n=34) ligatures were used. In male cats, PPG consisted of closed castration by spermatic cord knot (n=92) or ligature (n=91) while TAG (n=34) was an open castration by spermatic cord knot. A linear (surgical time) and a logistic regression (complications) model were designed. Significance was set at 0.05. For female PPG, clips and coagulation were the fastest procedures; placement of ligatures was most time-consuming. In male PPG, knot placement was significantly faster than ligation. In both sexes, very few intraoperative or wound complications were observed, irrespective of the surgical technique used. Surgical times in females (ligatures) as well as in males (knot) were significantly shorter for PPG than for TAG. PPG was as safe as TAG, yet took less time to perform and did not result in a greater rate of postoperative complications.

Immunohistochemical expression of potential therapeutic targets in canine thyroid carcinoma.

BACKGROUND: Thyroid carcinoma is a common endocrine tumor in the dog. Local invasive growth frequently precludes surgical excision and, in up to 38% of dogs, the tumor has already metastasized by the time of diagnosis. Therefore, it is important to investigate new treatment modalities that may be useful for the large number of dogs with inoperable tumors or metastatic disease. HYPOTHESIS/OBJECTIVES: To investigate the immunohistochemical expression of potential therapeutic targets in canine thyroid tumors. ANIMALS: 74 dogs with thyroid neoplasia. METHODS: Immunohistochemistry was performed for thyroglobulin, calcitonin, vascular endothelial growth factor (VEGF), p53, cycloxygenase-2 (cox-2), and P-glycoprotein (P-gp). RESULTS: Fifty-four (73%) tumors were classified as follicular cell thyroid carcinomas (FTCs) and 20 (27%) as medullary thyroid carcinomas (MTCs). Eighty percent of FTCs and all MTCs had a high percentage (76-100%) of neoplastic cells immunopositive for VEGF. Thirteen percent of FTCs and 50% of MTCs expressed cox-2. Seven percent of FTCs and 70% of MTCs expressed P-gp. No tumor was immunopositive for p53 expression. Expression of VEGF (P = .034), cox-2 (P = .013), and P-gp (P < .001) was significantly higher in MTCs compared to FTCs. CONCLUSIONS AND CLINICAL IMPORTANCE: VEGF is a potential therapeutic target in both FTC and MTC in dogs. Cox-2 and P-gp may be useful molecular targets in canine MTC.

Comparison between symptomatic treatment and lomustine supplementation in 71 dogs with intracranial, space-occupying lesions.

Brain neoplasia is diagnosed in an increasing number of dogs. Consequently, there is a higher need for an effective treatment. Chemotherapy is considered in cases where surgery or radiation is not optional. The objective of this retrospective study was to evaluate the difference in median survival time (MST) of dogs with intracranial masses, treated symptomatically with corticosteroids and anti-epileptic drugs, compared with the same symptomatic treatment supplemented with lomustine. The records of 71 dogs with intracranial masses were retrospectively evaluated. Fifteen dogs were treated symptomatically with corticosteroids and anti-epileptics, and 56 dogs received additional therapy with lomustine. There was no statistically significant difference in MST between both groups, being 60 and 93 days, respectively. Age, duration of symptoms, intracranial localization of the mass and intra- or extra-axial localization had no influence on survival time. However, female dogs survived significantly longer than male dogs.

The use of the HiSPECT bone scan in canine flexor enthesopathy and coronoid pathology.

In this study the use of the high resolution Micro-Single Photon Emission Tomography (HiSPECT) system with a radioactive bonemarker, (99m)Tc-oxidronate, was evaluated in dogs with coronoid pathology and/or flexor enthesopathy. Sixty-five elbows of 34 dogs were included. CT and HiSPECT were performed on all elbows, arthroscopy on 59. Tracer uptake in 8 anatomical regions was graded according to two models. Increased activity in the medial epicondylar region was associated with flexor pathology on CT (P=0.0002) and arthroscopy (P<0.0001) and increased uptake in the medial coronoid (P<0.0001) and the medial condylar area (P<0.013) with coronoid pathology. Uptake in the remaining areas was not associated with both pathologies. In conclusion, the improved resolution of the HiSPECT system allows identification of increased tracer uptake in the anatomical regions involved in coronoid pathology and flexor enthesopathy. This modality may improve the diagnostic potential of the bone scan in canine elbow disease.

Diagnostic intra-articular anaesthesia of the elbow in dogs with medial coronoid disease.

OBJECTIVE: Assessment of the effect of intra-articular anaesthesia on lameness caused by medial coronoid disease. METHODS: This study included 90 dogs that were evaluated for the complaint of unilateral forelimb lameness. All dogs were suspected of having an elbow problem for which orthopaedic examination and radiographs showed inconclusive findings. Following a short sedation, mepivacaine was injected intra-articularly to determine whether lameness was caused by a suspected elbow problem. This effect was compared with the final diagnosis based on computed tomography and arthroscopy. RESULTS: Out of 90 dogs, 78 (87%) dogs had an improvement of lameness after injection of the local anaesthetic, which confirmed the elbow joint as the primary source of lameness. A positive response was seen in all types of medial coronoid lesions. A false negative result was observed in 12 dogs (13%). CLINICAL RELEVANCE: Medial coronoid disease is represented by different types of pathologic lesions including chondromalacia, fissures, fragments, and medial compartment disease. Diagnosis may be difficult because of limited clinical or radiographic signs or a combination of both. Intra-articular anaesthesia can be a helpful diagnostic tool to localize the problem by eliminating pain and reducing lameness to a great extent in all types of coronoid lesions.

Effects of medetomidine and ketamine on the regional cerebral blood flow in cats: a SPECT study.

Brain perfusion can be investigated using single photon emission computed tomography (SPECT) and the intravenous injection of (99m)technetium ethyl cysteinate dimer ((99m)Tc-ECD). However, sedation using medetomidine, an α(2)-agonist, or anaesthesia using medetomidine and ketamine, an N-methyl-d-aspartate-(NMDA)-antagonist, may be required for SPECT studies in cats but can affect the regional cerebral blood flow (rCBF). The effects of medetomidine, with or without ketamine, on regional brain perfusion were therefore investigated in six cats under three conditions. Injection of tracer occurred before sedation or anaesthesia (condition A), following intramuscular (IM) sedation with medetomidine (condition M) or after IM anaesthesia with medetomidine and ketamine (condition MK). Medetomidine and medetomidine with ketamine caused a significantly higher total tracer uptake in all brain regions. Semi-quantification of brain perfusion gave lower perfusion indices in several sub-cortical regions in conditions M and MK, compared to A. Left-right differences were observed in the temporal cortex (A), the temporal, parietal cortex and the thalamus (M) and the frontal cortex (MK). A significantly higher perfusion index in the sub-cortical regions, compared to the whole cortex, was only present in condition A. This study showed that caution is needed when quantifying brain perfusion indices when using sedative or anaesthetic agents that may affect rCBF.

Expression of P-glycoprotein in the intestinal epithelium of dogs with lymphoplasmacytic enteritis.

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammatory disease of the stomach, the small intestine and/or the large intestine. Loss of integrity of the intestinal barrier may be an important factor in the pathogenesis of IBD. In dogs, lymphoplasmacytic enteritis (LPE) is one of the recognized forms of IBD. P-glycoprotein (P-gp) is a membrane-bound efflux pump constituting an important component of the intestinal barrier. Changes in P-gp expression at the level of the intestinal barrier may be important in the pathogenesis of canine LPE, as this may lead to variable protection against xenobiotics and bacterial products in the intestine. The aim of the present study was to evaluate the expression of epithelial P-gp in the intestine in dogs with LPE compared with disease-free animals. Formalin-fixed intestinal biopsy samples from 57 dogs with histopathological evidence of LPE were immunolabelled with anti-P-gp antibodies (C494 and C219). Endoscopic biopsy samples of the duodenum and colon from 16 healthy beagles were used as controls. None of the control dogs had P-gp expression in the apical membrane of duodenal enterocytes, but all had P-gp labelling at the colonic epithelial surface. Twenty out of 57 dogs with LPE had P-gp expression at the apical surface membrane of villus epithelial cells in the duodenum, jejunum and/or ileum. Six out of 16 colonic samples from dogs with LPE had decreased P-gp expression at the epithelial surface compared with controls. It is unclear whether these changes in P-gp expression in dogs with LPE are a cause or a consequence of the inflammation. The observed changes could affect bioavailability of therapeutic drugs used in LPE.

The effect of medetomidine on the regional cerebral blood flow in dogs measured using Technetium-99m-Ethyl Cysteinate Dimer SPECT.

Sedatives and anaesthetics are known to cause changes in the regional cerebral blood flow. In dogs intramuscular sedation with medetomidine, a potent sedative frequently used in veterinary medicine, is sometimes indicated prior to intravenous injection of (99m)Technetium-Ethyl Cysteinate Dimer ((99m)Tc-ECD) in brain perfusion studies using Single Photon Emission Computed Tomography (SPECT). Based on the knowledge of the distribution of alpha(2)-receptors in the brain, we hypothesized altered regional brain perfusion in dogs receiving medetomidine prior to (99m)Tc-ECD. Two conditions were compared in 10 dogs; tracer injection before and after intramuscular sedation with medetomidine. In our study, medetomidine caused a significantly higher tracer uptake in all brain regions. Semi-quantification of brain perfusion rendered a lower perfusion index in the subcortical region and an imbalance between left and right cortical perfusion induced by medetomidine. This study shows that caution is needed when quantifying the brain perfusion indices under medetomidine sedation.

Inspiratory stridor secondary to palatolingual myokymia in a Maltese dog.

A nine-year-old male Maltese dog was presented with an eight-month history of inspiratory stridor leading to exertional dyspnoea and cyanosis. Myokymic contractions in the palatolingual muscles were noticed and confirmed by electromyography. Brain computer tomography-scan showed ventricular dilatation. Cerebrospinal fluid analysis revealed a slightly elevated protein level. Treatment with slow-release phenytoin was unsuccessful and symptoms gradually worsened over the next nine months. At post-mortem examination a small pituitary adenoma was found. Apart from a single canine report of facial myokymia, this is the only other description of spontaneous focal myokymia in animals. Palatolingual myokymia has only been reported in one human being. Although the co-occurrence with a pituitary adenoma might be incidental, a paraneoplastic pathogenetic mechanism is proposed. Its unique clinical presentation adds a new, albeit uncommon, syndrome to the differential diagnosis of upper airway complaints in dogs.

A comparison of tepoxalin-buprenorphine combination and buprenorphine for postoperative analgesia in dogs: a clinical study.

The present study compares the analgesic effect of a tepoxalin-buprenorphine combination to that of buprenorphine alone in the 24 h peri-operative period in 20 dogs undergoing cranial cruciate ligament repair, which were randomly assigned to the two treatment protocols (n = 10). Additionally, possible side effects induced by tepoxalin were investigated. Analgesia was compared using a visual analogue scale (VAS) and a multifactorial pain scale (MFPS), by an anaesthetist blinded from treatment. Analysis of the overall VAS-scores showed a significant decrease over time in both treatment groups. The decrease in the two groups was not significantly different from each other. No significant differences were found between the MFPS-scores of both protocols. Potential side effects of tepoxalin were investigated by venous blood sampling before premedication and 24 h after extubation, a buccal mucosal bleeding time test and recording of vomiting, diarrhoea and adverse effects at the surgical site. Analysis of the blood parameters showed that fibrinogen levels were overall higher 24 h after surgery in both protocols, but were significantly more elevated in the tepoxalin group. No significant differences were found for the other blood parameters. Statistically, tepoxalin failed to improve analgesia induced by buprenorphine. There was no convincing evidence that the administration of tepoxalin was not associated with gastrointestinal side effects. There were no significant adverse effects on renal function and primary haemostasis.

Retroflexion of the urinary bladder associated with a perineal hernia in a female cat.

A case of retroflexion of the urinary bladder into a bilateral perineal hernia in a female domestic shorthaired cat, three weeks postpartum, is reported. The bladder was repositioned and a cystopexy performed. A pelvic ostectomy was also carried out in order to alleviate the narrowing of the pelvic canal caused by an untreated acetabular fracture. Bilateral perineal herniorrhaphy was performed.

The effects of intrathoracic pressure during continuous two-lung ventilation for thoracoscopy on the cardiorespiratory parameters in sevoflurane anaesthetized dogs.

The cardiopulmonary effects of different levels of carbon dioxide insufflation (3, 5 and 2 mm Hg) under two-lung ventilation were studied in six sevoflurane (1.5 minimum alveolar concentration; MAC) anaesthetized dogs during left-sided thoracoscopy. An arterial catheter, Swan-Ganz catheter and multianaesthetic gas analyser were used to monitor the cardiopulmonary parameters during the experiment. Baseline data were obtained before intrathoracic pressure elevation and the measurements were repeated at intervals after left lung collapse induced by insufflation with carbon dioxide gas. The intrapleural pressure levels used were 3, 5 and 2 mm Hg. Arterial blood pressures, cardiac index, stroke index, left and right ventricular stroke work index, arterial haemoglobin saturation, arterial oxygen tension and systemic vascular resistance decreased significantly during hemithorax insufflation, whereas heart rate, right atrial pressure, mean, systolic and diastolic pulmonary arterial pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance and arterial carbon dioxide tension significantly increased during intrapleural pressure elevation. Although carbon dioxide insufflation into the left hemithorax with an intrapleural pressure of 2-5 mm Hg compromises cardiac functioning in 1.5 MAC sevoflurane anaesthetized dogs, it can be an efficacious adjunct for thoracoscopic procedures. Intrathoracic view was satisfactory with an intrapleural pressure of 2 mm Hg. Therefore, the intrathoracic pressure rise during thoracoscopy with two-lung ventilation should be kept as low as possible. Additional insufflation periods should be avoided, since a more rapid and more severe cardiopulmonary depression can occur.

Thoracoscopic anatomy of dogs positioned in lateral recumbency.

In four healthy, adult male German shepherd dogs, thoracoscopy was performed to provide a detailed description and illustration of the endoscopic anatomy of the normal intrathoracic structures of dogs. The dogs were anesthetized and placed in left or right lateral recumbency. The cannula and the endoscope were advanced into the thoracic cavity via entry of the free upper side in the dorsal third of the eighth intercostal space. Most intrathoracic structures of the left and right hemithorax were endoscopically visible. During the four thoracoscopic procedures, endoscopic photographs were taken and are illustrated in this paper. A sound knowledge of the anatomy of intrathoracic structures is a prerequisite for diagnostic and therapeutic thoracoscopy.

Atlantoaxial cartilaginous exostosis causing spinal cord compression in a mature Bernese mountain dog.

Cartilaginous exostosis developed in the atlantoaxial region of a three-and-a-half-year-old Bernese mountain dog. The dog exhibited ataxia in the hindlimbs and flailing movements in the forelimbs. On survey radiographs of the cervical spine there was a focal calcified mass between the dorsal arch of the atlas and the spinous process of the axis. Lumbar myelography revealed severe dorsal spinal cord compression. The mass was removed surgically and the dog made a complete recovery. Histopathology of the excised mass was consistent with a diagnosis of cartilaginous exostosis.

Intravenous self-administration of heroin/cocaine combinations (speedball) using nose-poke or lever-press operant responding in mice.

Acquisition and dose-related self-administration of heroin (H)/cocaine (C) combinations in C57BL/6 x SJL mice were studied in nose-poke or lever-press operant responding procedures. C57BL/6 x SJL mice readily acquired self-administration in both operant procedures with a combination of doses known to be ineffective when each drug was used alone (H: 15 microg/kg and C: 150 microg/kg per injection). Similar numbers of infusions were obtained under conditions of fixed-ratio (FR) 3 versus 1 for the nose-poke and lever-press responses, respectively. Dose-effect curves for heroin:cocaine combinations revealed a pattern corresponding to a leftward shift of the dose-response for intravenous cocaine self-administration. Curves were similar whether generated with 1 or 3 days of availability per dose, or including subjects that did not respond preferentially (> 70% responses) to the hole or lever associated with drug delivery, along with those that did. Motor activity induced by a combination of low doses for each drug was examined (H: 0.375 mg/kg and C: 3.75 mg/kg, i.p.). Under these conditions, the combination of both drugs induced an initial cocaine-like stimulation of horizontal activity, in contrast to the tendency of heroin to decrease activity. It is concluded that heroin:cocaine combinations used in the present study had reinforcing effects in C57BL/6 x SJL mice, and produced a cocaine-like effect in the early part of drug-induced activity sessions, followed by a locomotor profile corresponding to the average of both drugs.